(a) Field of the Invention
The present invention relates to a spatial multiplexing detection system and method by use of a MIMO (Multi Input Multi Output) technology.
(b) Description of the Related Art
The MIMO technology aims at increasing frequency efficiency, and it represents a method for using multiple antennas at a transmitter and a receiver. The MIMO technology concurrently transmits different data through respective antennas of the transmitter, and hence, it increases the frequency efficiency by as much as the number of antennas at the transmitter.
In detection in the MIMO system, multiple data streams are concurrently received and separated. Therefore, the receiver of the MIMO system processes the case in which a single terminal receives multiple data streams and the case in which the data streams are respectively other users' signals in the same way.
The MIMO system uses multiple transmit and receive antennas to improve data rates in a given band, as opposed to the existing SISO system, and an increase of the frequency efficiency depends on the degree of independency among various transmit and receive channels.
Since the independency of MIMO channels follows an interval between antennas, the number of antennas is limited in a terminal, and an increase in the data rates in an uplink is restricted. A base station which is a receiver, however, is not limited to the number of antennas or increase of data rates.
A method for maximizing a channel application in this condition is to allow a number of users that can be detected by the base station to access the channels.
When many users use the channels as described above, if the users are assigned without any rule, the channel capacity may be worsened by channel characteristics such as a correlation between the channels.
To overcome the problems, it is needed for a base station to use the channels of the respective users to assign the users so that the channel capacity may be maximized, and a sub-optimal algorithm with substantially less performance deterioration is required for simple realization.